Shure Incorporated 222 Hartrey Avenue Evanston IL 60202-3696 U.S.A. T Wireless System SERVICE MANUAL CHANGE NOTICE T1/TC1 WIRELESS BODY-PACK TRANSMITTER Changes and corrections have been made to the Service Manual for the T1 Body-Pack Transmitter. To update your Service Manual, remove the pages identified in the tables below and replace them with the pages attached to this Change Notice. Note that there are no changes to pages not specifically identified in the tables below.
T1/TC1 Body-Pack Transmitters 25C1016 (CC) Characteristics General This section tells how to service and align the T1G, T1, TC1, and the discontinued T1P Body-Pack Transmitters (Figure 1). These single-channel, crystal-controlled units operate in the 169 MHz to 216 MHz VHF Band.
Shure T1 Body-Pack Transmitters Circuit Description The T1 transmitter contains one circuit board which comprises an audio and an RFsection. It is intended for use with the matching T3 and T4 receivers. Audio Section Input: Audio signals enter via a 1/4-in.
Shure T1 Body-Pack Transmitters L209, diode D201, capacitor C214, and capacitor divider C224 and C230. Frequency and Temperature Stability: To ensure frequency stability despite changes in the battery voltage, regulated 5 Vdc bias is applied to the varactor diode and to the base of Q201. Temperature compensation is provided by C224, C230, and C214.
Shure T1 Body-Pack Transmitters Antenna: This is a quarter-wavelength, permanently attached, flexible wire. The ground plane of the circuit serves as an untuned counterpoise capacitively coupled to the body of the user. Spurious Emissions: To minimize the production and radiation of spurious emissions and harmonic energy, and to promote stable operation, the collector of each RF stage is separately decoupled from the 9-volt supply by ferrite chokes, resistors, and bypass capacitors.
Shure T1 Body-Pack Transmitters Preliminary Tests Listening Tests Before disassembling the unit, operate it to determine whether it is functioning normally. Focused Testing: First and most important: Review any customer complaint or request and focus your listening and functional tests on any reported problem. For example, for “short range” and “drop-outs” complaints, perform only the RF tests in this section.
Shure T1 Body-Pack Transmitters 2. Set the RF generator as follows: Amplitude: –20 dBm Modulation: 1 kHz Deviation: 15 kHz Frequency: T1 operating frequency 3. Connect the audio from the unbalanced output to the audio analyzer with a 3.3 kΩ load. Turn the Volume control all the way up. 4. For the associated T3 or T4, verify the following: S audio level is 400 mVrms ("90 mV) S thd = <0.75% B: Check the Transmitter 1. Disconnect the signal generator from the receiver.
Shure T1 Body-Pack Transmitters Disassembly and Assembly To access the printed circuit (pc) board, disassemble the transmitter. CAUTION Observe precautions when handling this static-sensitive device. Disassembly 1. Slide open the battery-compartment cover and remove the battery. 2. With a #1 Phillips screwdriver, remove the four screws securing the back of the case, and set them aside. 3. Carefully separate the top and bottom halves of the case to expose and lift out the pc board.
Shure T1 Body-Pack Transmitters Converting a T1P to a T1 Because direct replacements for the lavalier microphones used in the T1P are no longer available, the best way of replacing the microphones in these earlier units is to replace the lavalier header with a male Tini Q-G connector, which will allow the unit to accept a WL93 or other microphone that has a mating connector. Changing the connectors in effect converts the T1P into a T1 unit. Parts Needed Microphone with a female Tini Q-G connector (e.g.
Shure T1 Body-Pack Transmitters Service Procedures Reference Material The Shure Wireless Systems: T Series User’s Guide provides a description, information on operation and troubleshooting, and technical data. Special Equipment The Wireless Service Equipment manual covers the standard items needed for servicing the transmitters. If you do not have the modified SC4 receiver described there, you will need an appropriate receiver (usually T3 or T4) to verify that the transmitter is working properly.
Shure T1 Body-Pack Transmitters Table 2 T1 Series System Operating Frequencies Group Crystal Code Freq. (MHz) T V 169.445 T AC 170.245 T W 171.845 A CA 176.200 A CC 177.600 A CE 182.200 A CF 183.600 B CG 186.200 B CL 192.200 C CQ 202.200 C CV 208.200 Changing the Frequency The operating frequency of the T1 transmitter may be changed within a specific group by changing the crystal on the pc board. (For Group information, see the preceding section.
Shure T1 Body-Pack Transmitters Pins 1 2 3 4 S The Gain pot (R125) is preset to its midpoint. S The 400 Hz high-pass and the 30 kHz low-pass filters on the audio analyzer are activated.
Shure T1 Body-Pack Transmitters TP2 TP1 TP5 TP3 TP9 (–) Limiter components (not in all units) TP6 TP8 (+) TP7 TP4 Test Points TP1 Audio In, J104, pin 3, Model T1-P. TP2 Audio In, J103, center conductor of 1/4-in. phone jack, Model T1-G. TP3 Audio TP4 Antenna Output TP5 Intermediate Output TP6 9 Vdc TP7 5 Vdc TP8 (+) Battery TP9 (–) Battery Figure 3. Pcb Side 1 Display Checks 1. Connect the 9 Vdc power supply: the green LED should glow. 2.
Shure T1 Body-Pack Transmitters 6. Connect the 50 Ω output cable to the frequency counter. If the frequency is off by more than 5 kHz, adjust L209 to set the carrier frequency to FC ±1 kHz. 7. Reconnect the 50 Ω output cable to the spectrum analyzer. Confirm that the output power remains within specification. If necessary, readjust C217 and C215. B: Spurious Emissions 1. Set the scale on the spectrum analyzer back to 10 dB/div. 2. Check the level of spurious emissions up to 1 GHz.
Shure T1 Body-Pack Transmitters tio button to perform the relative measurement in the next subsection. T1G (1/4I Pins 1 2 3 4 T1P (connector J104) 3 4 1 T1 (Tini “Q-G,” J201—solder side) 2 R217 L209 phone jack, J103) Y201 C217 C215 O TP4 O TP3 J101 – Battery Terminals J102 + R125 R130 M O u n t e “Power On” LED (green) (D101) LED (red) “Low Battery” Mute (D102) Switch (S101) out Power On/Off Switch (S102) Audio Analyzer in Receiver Figure 4.
Shure T1 Body-Pack Transmitters F: Deviation Reference Voltage 1. Turn off the transmitter. 2. Set the RF signal generator as follows: (a) Enter the carrier frequency. (b) Select FM modulation and enter the following: Modulation Source: Int 1 kHz FM Deviation: ±15 kHz Amplitude: –38 dBm 3. Select a receiver for the T1, making sure it is set to the same frequency as the transmitter. Disconnect the receiver’s antenna (non-diversity) or antennas (diversity). 4.
Shure T1 Body-Pack Transmitters 7. Set the audio analyzer to measure distortion. Verify that the audio distortion at the unbalanced output of the matching receiver is less than 0.5%. If necessary, adjust R130 to obtain minimum distortion. Note: For T1G transmitters Only: After completing the alignment, turn the audio Gain potentiometer (R125) all the way down (fully clockwise as viewed from the top side of the circuit board).
Shure T1 Body-Pack Transmitters Bench Checks Dc Power n Verify that 9 Vdc (±0.35 Vdc) is present at TP6. If this voltage is low, trace the circuitry back to the power supply to see where the loss occurs. Check: S power switch S bias on Q105 S L101 S circuit-board ground for 0 V n If you have a short to ground from 9 V, try isolating different parts of the circuit. Narrow it down to the RF or audio section. Look for foil shorts, solder bridges, and capacitors that have been installed backwards.
Shure T1 Body-Pack Transmitters n Check the bias voltage (`4 Vdc) on pins 8, 9, and 10 of U102. If the correct voltage is not present: S Make sure the Mute switch is set to “On.” S Trace the bias circuit from the 5 V line through R104 to pin 10 of U102. S Check the values in the feedback path from pin 8 to pin 9 of U102, and the path to Q104 and pin 16 of U101. Frequency Problem n Make sure the RF carrier is at least 10 dB higher than the spurious emissions, to allow the frequency counter to lock on.
Shure T1 Body-Pack Transmitters Excessive Current Drain n Try readjusting C215 for lower current drain while maintaining output power to specification. If the current drain is still excessive, check for the following: S short S wrong resistor value S shorted capacitor n As a last resort, try changing Q204. Deviation n If R217 cannot be adjusted to obtain a "15 kHz deviation, try to isolate the problem to the audio or RF section by doing the following: S If TP3 does not measure –2.
Shure T1 Body-Pack Transmitters Notes: Notes: 20 25C1016 (CC)
Shure T1 Body-Pack Transmitters Replacement Parts and Drawings On the next page, the parts are listed according to the designations from the pc board and schematic (see Figures 5 and 6, and the schematic). Parts shown on the circuit diagram and not listed below are available through electronic-parts distributors. On the pages following the parts list are the drawings of the printed circuit boards and the schematics. Product Changes This section briefly describes significant changes to the T1.
Shure T1 Body-Pack Transmitters Table 1 T1 Replacement Parts Drawing Designation Description Source: Shure Part No. (Commercial Alternate) A1 Printed circuit board assembly T1G: (Order the antenna, and 1/4-in phone jack separately) Printed circuit board assembly T1P: (Discontinued, for modification see pg. 8) Shure T90__8552 [See Table 2, to determine the Frequency Code in the underlined space. e.g. T90CF8552].
Shure T1 Body-Pack Transmitters Drawing Designation Description Source: Shure Part No.
Shure T1 Body-Pack Transmitters 34AB8459F Figure 5. Pcb Side 1 Figure 6.
Shure T1 Body-Pack Transmitters TP 5 TP 2 TP 1 TP 4 TP 3 TP 9 (–) TP 6 TP 7 TP 8 (+) TP – Test Points TP 1 Audio In, J104, pin 3, Model T1–P. TP 2 Audio In, J103, center conductor of 1/4 in. phone jack, Model T1–G. TP 3 Audio TP 4 Antenna Output TP 5 Carrier Output TP 6 9.0 Vdc TP 7 5.0 Vdc TP 8 (+) Battery TP 9 (–) Battery Figure 7. Earlier Version of T1 Pc Board (Side 1) Figure 8.
Shure T1 Body-Pack Transmitters [Insert: Earlier Version of T1 schematic (81/2 11) as p.
+5V R106 TP2 N13 .022uF C133 150pF C134 150pF D103 L102 C105 5 3 1 2 2 CW R119 1K 3 C120 4.7 X 16V N19 N82 C110 + R145 GAIN R112 1.0 X16V C106 1.0 X 16V N20 R115 16.5K C111 1 R125 2.0K 100K ANTI–LOG TAPER 1 + N17 6 N23 FOR AUDIO INPUT: T1G WILL HAVE J103 PRESENT ON THE FINAL PRODUCT. T1P WILL HAVE J104 PRESENT ON THE FINAL PRODUCT. 100K 7 U102 C 188A120 C137 4 14 150pF U102A 188A120 R117 24.9K + 188A01 2 3 U101 2 L101 162A03 N35 C126 + 4.
+5V *Audio In J104 R103 1M C136 4 .0039 N9 N8 C132 7 3 N5 N76 10K R110 C105 N4 499 470pF N13 1.0 X 16V C133 150pF C134 150pF L102 TP2 Pin 9 of U101 R107 5 3 .022uF 1 U102C 188A49 6 2 1 R119 1K 2 C12 4.7 0 pF 16V 24.9K 7 2 CW 3 R125 1 100K Anti-log Taper R145 N82 C110 + 2.0K R112 N19 N20 16.5K 1 pF 16 V 4.99K C102 47 pF 10V +9V MC33179DR2 12 N22 12 4 14 11 2 N25 TP6 N37 L101 162A03 N35 Green R136 6.19K J101 D101 C126 4.
+5V *Audio In J104 R103 1M C136 4 .0039 N8 C132 7 3 N5 N76 10K R110 C105 N4 499 470pF N13 1.0 X 16V C133 150pF C134 150pF L102 TP2 162T06 Pin 9 of U101 R107 5 3 .022uF 1 U102C 188A49 6 2 1 R119 1K 2 C12 4.7 0 pF 16V 24.9K 7 2 CW 3 R125 1 100K Anti-log Taper R145 N82 C110 + 2.0K R112 N19 N20 16.5K 4.99K C102 47 pF 10V +9V MC33179DR2 12 4 14 12 11 2 14 N25 + U101A TP6 Q105 N37 L101 162A03 N35 Green R136 6.19K J101 D101 C126 4.
